MINNEAPOLIS — After Prince had to be revived from a drug overdose a week before his death, one friend told the musical superstar that he needed to stop taking painkillers. But Prince said he couldn’t — his hands hurt so much that if he quit, he’d have to stop performing.

“This piano tour I think was getting to his hands,” singer Judith Hill told investigators, according to a transcript of her interview.

Those words, found amid hundreds of pages of interviews between investigators and Prince’s closest confidants, provide insight into just how much the man known for his energetic performances and larger-than-life personality was suffering. The documents open parts of Prince’s life that the intensely-private celebrity tried to keep from even his closest confidants.

“How did he hide this so well?” Prince’s closest friend and bodyguard Kirk Johnson said in an interview with detectives. While Johnson said he didn’t realize that opioids were a problem until that overdose, he had noticed Prince was unwell before that and took him to a doctor.

In their zeal to protect Prince’s privacy, Carver County Attorney Mark Metz said some of the singer’s friends might have enabled him.

Prince was 57 when he was found alone and unresponsive in an elevator at his Paisley Park studio compound in suburban Minneapolis on April 21, 2016. An autopsy found he died of an accidental overdose of fentanyl, a synthetic opioid 50 times more powerful than heroin. Authorities say it is likely Prince didn’t know he was taking the dangerous drug, which was laced in counterfeit pills made to look like a generic version of the painkiller Vicodin.

The source of those pills is unknown and no one has been charged in Prince’s death.

Dr. Michael Todd Schulenberg admitted that he prescribed another drug, oxycodone, under Johnson’s to protect Prince’s privacy, and paid $30,000 to settle allegations the drug was prescribed illegally.

Privacy is a theme in interviews with investigators. Joshua Welton, who co-produced some of Prince’s work, and Hannah Welton, the drummer in the Prince-created band 3rdEyeGirl, said they were like Prince’s family.

Joshua Welton described Prince’s inner circle at the time of his death as “very, very, very, very, very tight” — including Johnson, assistant Meron Bekure and the Weltons. He said he had seen little of Prince’s sister, Tyka Nelson, in recent years. “He’s made comments like you guys are more family to me than my blood relatives,” Welton said.

Johnson and Hill were on Prince’s plane when he overdosed on the way back from an April 14, 2016, concert in Atlanta. Hill said that Prince told her he was depressed, enjoyed sleeping more than usual and was incredibly bored. He told her after his show that he thought he was going to fall asleep on stage.

The plane made an emergency landing in Moline, Illinois, and after Johnson carried Prince from the plane “like you would carry a little kid or a baby,” paramedics had to use two doses of a medicine that reverses the effects of an opioid overdose. When Prince took a large gasp of air and woke up, he looked at Johnson without saying anything and Johnson told paramedics, “Prince feels fine.”

At the hospital, Prince refused medical tests. He told Hill that he had just mixed two pills — that he was a good judge of his body and wouldn’t do it again. But when she told him “no more pills right?” he wouldn’t agree.

“He said something like well then that means I can’t perform because my hands are hurting. My hands hurt,” according to a transcript of her interview with investigators.

Investigative materials released Thursday include several other interviews, documents, photos and videos. There are pictures of pills that were found in various bottles in several different rooms. Authorities have said many of those pills were not in their proper containers, and many were counterfeit.

The documents include interviews with Schulenberg and Prince’s inner circle, including Johnson, who told investigators he had noticed Prince “looking just a little frail,” but said he did not realize he had an opioid addiction until the overdose on the plane. After that, Johnson said he and others reached out to an addiction specialist.

But Johnson had initially contacted Schulenberg, his own doctor, to treat Prince in the fall of 2015. Schulenberg told investigators that Johnson texted him on April 7, 2016, saying Prince was complaining of numbness and tingling in one of his legs and in his hands and had vomited the night before. Schulenberg prescribed some medications under Johnson’s name and gave Prince an IV, according to documents.

Schulenberg asked Prince if he was taking anything for his hands and Prince said yes, but “did not know what it was,” documents show.

Johnson also called Schulenberg on the fateful day of the Atlanta concert before the flight on which Prince overdosed and asked the doctor to give Prince a painkiller. Authorities say Schulenberg did so — under Johnson’s name. Johnson contacted Schulenberg again on April 18, and expressed concern that Prince was struggling with opioids.

Schulenberg last treated Prince the night before he died, conducting a urinalysis that tested positive for opioids. Meanwhile, Johnson and others had reached out to addiction specialist Howard Kornfeld, who dispatched his son to Paisley Park to try to convince Prince to seek treatment.

Andrew Kornfeld showed up the following morning. He was among those who found Prince dead.